PROTECT IV and MCS for High-Risk PCI

Gregg Stone, M.D., primary investigator of the PROTECT IV randomized controlled trial, discusses data supporting the use of mechanical circulatory support (MCS) for high-risk PCI. This SCAI 2021 presentation is titled, “PROTECT IV: New Data Supporting Complete and Supported Revascularization.”

Dr. Stone begins with an overview of the clinical need for mechanical circulatory support for high-risk PCI. He discusses the clinical and anatomic characteristics of this patient population, who tend to have comorbidities, complex coronary artery disease and hemodynamic compromise. He describes these patients as being at high risk for procedural complications during PCI, noting that they may not receive complete revascularization and that physicians may alter their stenting techniques in such complex cases.

Dr. Stone then presents the potential benefits of MCS for high-risk PCI, which he states include:

• Reducing procedural complications, which can improve early outcomes
• Enabling optimal stent implantation and complete revascularization, which can improve late outcomes through reduced restenosis, reduced stent thrombosis and improved recovery of left ventricular function
• Potentially providing renal protective effects, leading to reduced acute kidney injury or long-term renal preservation

He reviews existing data supporting the use of MCS for high-risk PCI, starting with the BCIS-1 trial and PROTECT II randomized controlled trial, yet notes that MCS for high-risk PCI is a topic that’s not extensively covered in guidelines. 

Dr. Stone then describes the PROTECT IV trial, which enrolled the first patient in April 2021. “And this is really going to be a large-scale, international, pivotal randomized trial to look at the benefits of mechanical circulatory support both in the short-term and the long-term in high-risk patients with complex coronary disease undergoing PCI.” He explains that between 1252 and 2500 patients will be randomized to receive either Impella CP® or control (no MCS or IABP).

Dr. Stone states, “Our hypothesis is that by providing hemodynamic stability during high-risk, complex PCI, Impella® will facilitate improved stent optimization and more complete revascularization that will translate into improved early and late outcomes.” He identifies the primary endpoint as a composite rate of all-cause death, stroke, MI or all cardiovascular hospitalizations at three years. He also explains, “We have numerous substudies including looking at the utility of right heart catheterization to guide these procedures and device weaning, a renal function substudy to look to see if there really is an effect on renal preservation and a very interesting viability substudy using cardiac magnetic resonance (CMR) imaging at baseline and at six-month follow-up to determine if viability really should dictate as to which lesions should get revascularized and whether or not that affects prognosis.” 

Dr Stone concludes by stating that hopefully, in about five years, PROTECT IV results will provide the “final word” on mechanical circulatory support for high-risk patients undergoing complex PCI.